G’day everyone and welcome to 100 Climate Conversations I’m Benjamin Law. Today is number 46 of 100 conversations that happen here every Friday at the Powerhouse museum and online which presents 100 visionary Australians taking positive action to respond to the most critical issue of our time, which is, of course, climate change. Now we’re recording this today in the Boiler Hall of the Powerhouse museum. And before it was home to the museum, it was the Ultimo Power Station. It was built in 1899 and it supplied coal powered electricity to Sydney’s tram system in the 1960s. So, it’s in this context and in the belly of this industrial artefact that we shift our focus towards the innovations of the net zero revolution.

We’re really grateful to be having this conversation today on the Unceded Lands of the Gadigal. First Nations people on this continent have been sharing knowledge and stories here for tens of thousands of years. Combined they are the oldest continuing civilisation this planet has ever known. They’re the world’s first scientists, engineers, agriculturalists, mathematicians, and they mastered how to live sustainably on such a dry continent, which is a feat, of course, that we’re still struggling with now. So, we’re really grateful to Elders past and present that we can continue sharing knowledge here on what is and what will always be Aboriginal land.

Our guest today is the chief botanist and director of research at the Australian Institute of Botanical Science, Royal Botanic Gardens and Domain Trust, Sydney. With over 30 years of experience performing vital scientific research, he’s also a senior scientific advisor to the Government advocating for plant conservation. Can you please join me in welcoming today, Brett Summerell.

Brett, I want to go right back because there are many things that capture our interest when we’re growing up or thinking about what we want to do with their adult lives. For you, I’m wondering, all of us are surrounded by plants, but what drew your attention to them and why were you fascinated with them so much?

So, I think it was a gradual thing. I got interested in gardening. I got interested in, you know, cultivating and culturing a range of indoor plants and having a veggie garden. Those sorts of things. Over a period of time, I think it was a very gradual process that eventually led me to thinking I’m really interested in how plants grow, why plants grow, maybe why they get sick. And taking that on as a focus for my studies when I went to university.

Yes. Yes. So, there is this whole thing of plant blindness. That it’s this green backwash that everybody has – hopefully everybody has around them, and an opportunity to interact with. And so, we do horrendously take it for granted. But plants are fundamental to life. They are the basis of all life. They’re the basis of everything that you eat. They’re the basis for the oxygen that you breathe in every single second of the day. They’re critical for that. They are still the most cost-effective means by which carbon dioxide is absorbed from the air. So, they are completely fundamental for everything. Most of our drugs either originated from plants or fungi in some way, or they have been adapted from them. Everything about what we do, our clothes, our food, our habitat, our houses, and then all of the creatures that we also depend on. So cattle, sheep, all of those things are all completely dependent on plants for their life. And for our life.

I wanted to ask that because I guess all of us are surrounded by plant life, trees, vegetation, the plants that we might even be tending to in our lives. And it’s probably a presence that a lot of us take for granted. I wonder, could you tell us why we should be interested in plants?

We only exist if plants exist.

Yes.

Now, you’ve been at the Botanic Gardens for, I think, 34 years now. Is that right?

34 in January.

Wow. What’s that journey been like? Where was the starting point for you? What was the first encounter there?

It was by accident, and I didn’t expect it would last this long. So, I did an agricultural science Degree at the University of Sydney and then did a PhD working on the impact of certain diseases in in wheat fields in northern New South Wales. So, really broadacre cropping systems. When I got to the end of my PhD, it just happened that there was a job advertised at the Botanic Gardens for a plant pathologist, somebody who works – a plant doctor, if you like. And, you know, I just loved it. It’s just has so many aspects to it, so many opportunities to do some really interesting, cool things, either working with the community, working in three of the most spectacular places, just to work in and habitat in Sydney, but also the opportunity to do all sorts of things out in the natural ecosystems around Australia and around the world.

So, when I first started at the gardens, it was very much I was a scientist dealing specifically with issues of plant health. And as the gardens have evolved, we’ve become much more focused in plant conservation and having a broader remit in the community and across the country. And so, my role has changed there. And inevitably, as you stay at a place longer and have some ability to influence things, you move up in the management chains. And so now I have responsibility for a really large team of people doing all sorts of interesting plant science activities, but also the education programs at the garden. So, it’s about building the facilities, employing and making sure that the brightest minds in plant science have the facilities and the resources needed to do their work and looking after and supporting the education programs which have a huge influence in terms of the number of kids that come into the gardens to discuss issues about why plants are important, why First Nations culture is important, why sustainability and climate change and all of those things that we can do to improve the situation.

As well as plant life. You’re also an expert on – is it fungi or fungi?

Technically, both are correct. So, depending on who you listen to, and inevitably I’ll swap between fungi and fungi. But fungi is the usual.

Okay, well, fungi, fungi. Potato, potato. Right? And you’ve described over 120 species new to science, is that right?

Yes. So, it’s interesting. You know, Australia is a super biodiverse continent. We think we know about 85 per cent of the plant species that have been formally scientifically described, they’re obviously known before. But with fungi, they’re very, very underexplored, I suppose is the proper word scientifically. And so, there’s lots of microscopic fungi that’s lots of microscopic soil dwelling fungal species that have not been scientifically described. So, we think we know about 10 per cent of the –

Wow, only 10.

10 per cent of those species, yes. So, every time you look at a leaf spot or you pick up something out of a bit of soil, you’re potentially, and look very likely describing a new form of life in that way.

I’m glad we’re having this conversation because it feels like as though even though you’ve been in this field for quite some time, looking at plants and fungi, that fungi seems to be in the zeitgeist at the moment in terms of bigger conversations, cultural conversations. I mean, the Icelandic singer Björk, for instance, her last record is all about fungi. Researchers recently turned fungi into computers in a scientific breakthrough. So, it feels like there are so many disciplines and realms of knowledge that are invested in what fungi is and what it’s capable of. What about for you? What makes fungi so compelling and fascinating to you?

I think they’re really amazing, an amazing group of organisms. You know, they’re potent producers of a whole range of secondary metabolites, whether you’re talking about psilocybin and all of those things that may have really interesting properties for medicine and for psychological work through to the fact that underneath the soil is just this huge mass of fungal networks connecting trees, connecting plants together. It’s been somewhat dismissively talked about as the Wood Wide Web, but there’s certainly an opportunity for plants to communicate in ways which we probably don’t really understand through this fungal network. So, I think they’re amazingly connected through that soil service. They’re probably the largest organisms on the planet, single organism on the planet. You can get, you know, a single fungal clone that can be hectares in size, there in all sorts of different ways.

And of course, their critical role as decomposers and recyclers is such an interesting way in which we can think about them in terms of how they’re turning over the nutrients in the environment in a way that’s really critical for the functioning of that environment. So, every way you look at them, there’s fantastic things and you know, mushrooms are just really cool.

How have you seen or how are you observing plant life and fungi being affected by how climate is changing?

It’s in so many different ways, and that’s probably reflective of the fact that you make these changes to an environment and to the climate, the ways in which it will have an impact is multiple and so multifaceted. It’s very, very difficult to put a complete handle on it. But, you know, as temperatures change, distributions of plants change.

The 2019-2020 fires were just the most horrendous example of how life in this country can be affected by a climate induced disaster like that. So, we undoubtedly saw species become extinct because of those fires. But certainly the distribution and the density and frequency of a lot of species was dramatically impacted by those fires. And then you can’t dismiss the impact of the floods since that period of time, which has had both negative and positive aspects in terms of plant life. But, you know, we’ve seen whole riverine ecosystems basically removed by the intensity and the ferocity of those floods and the like. Those ecosystems just are not there and they’ll take God knows how long for them to be reinstated and recover from those sorts of situations. So, you see all sorts of different ways in which plant life and all of the creatures that depend on them have been affected.

I wonder when it comes to the Botanic Gardens themselves, you know, those of us who love the Botanic Gardens, engage with the Botanic Gardens, probably think of it as a lovely place to look at plant life, to have lovely picnics, to engage with it in that way. And maybe the assumption there is that climate change will, of course inevitably affect the Botanic Gardens too. But are there ways in which the Botanic Gardens actively addresses the challenges of climate change too?

In the gardens per say, yes, it’s really important. We know, for example, in the Sydney gardens that with sea level rise, the sea wall – what do we do there? How do we stop the ocean actually coming into and affecting the gardens as temperatures change? Do we need to change the suite of species that we have on display there? Because some will just not be able to cope with it. How do we moderate watering regimes and the like so that we can keep those big trees alive and going through into the future? So, there’s going to be a need for a lot of infrastructural changes, more controlled and moderated irrigation processes, protecting the seawall from inundation, from the ocean. So, lots of things in those spaces.

And then when you get to our gardens at the Australian Botanic Garden at Mount Annan and the Blue Mountains Botanic Gardens up at Mount Tomah, we need to be really starting to think about the impact of both drought and floods and fire in particular. Now in 2019-2020, the Blue Mountains garden, the cultivated garden, about a quarter of it was burnt. So, we saw the firsthand impact of these climate change impacted disasters having an effect on a botanic garden.

So, the Botanic Gardens then need to adapt in terms of how it’s going to face the new realities and risks of climate change. What about the Botanic Gardens’ role in educating the broader public about the impacts of climate change and also about the role in research in mitigating the effects of climate change more broadly?

We have a huge program in educating. So, it’s a component of advocating and highlighting the impacts of climate change on plants with very much a focus on plant conservation. But then Sydney gardens, we get 50,000 schoolkids come into the gardens for educational programs, for the curriculum-based education programs a year. And it’s an opportunity to talk to them about the importance of plants. Talk to them about the importance of culture and the like, but also to talk to them about what’s happening out in the world and the little things that they can do and trying to make that as positive as possible so that you can demonstrate all of the good things that can be done and how they can go home as little fierce advocates for sustainability. Nothing more fierce than a year five or year six student coming home and trying to change their parents’ and their grandparents’ perspective so that there’s a whole work in that space.

But also, in terms of our broader role in terms of conservation and mitigation, it’s about ensuring that all of the species that are affected by or potentially affected by climate change events, that we’ve got back up plans for them. So, that really is a big part of our role at the moment, is to make sure that we have as many species across New South Wales and across the country in our seed bank out at the Australian Botanic Gardens, but also understanding what the likely impacts of climate change and other types of environmental change are on them. So, we have backup plans for them.

So, through Royal Botanic Garden and Domain Trust Sydney has been collecting and storing seeds throughout its history and it opened the Australian plant bank, I believe, in 2014. So, this is a place for world leading botanical research and public learning that also incorporates the largest native plant conservation seed bank in the country. Tell us about how this came about and how it works.

Botanic gardens in general have collected seed and stored them and exchanged them with other botanic gardens, and that was the role of botanic gardens, right way, way back in the 1800s or whatever. But our focus since about 2000 has been collecting species, particularly those that are at risk of some sort of extinction. So, we have been collecting those seed and storing them originally in a glorified cafe restaurant type fridge. Now, we’ve – since 2013, 2014 – we’ve built the Australian Plant Bank out at Mount Annan and incorporated in that is this concrete bunker, if you like, which has a number of high-tech fridges and freezers right down to cryopreservation under on liquid nitrogen as opportunities to store well collected, well-maintained representatives of a whole range of different species of plants in the seed bank. It’s an insurance policy, if you like.

The name ‘bank’ is very, very representative of what we do. We go out and collect it deposited in the bank and then when we need to withdraw it from the bank, either to grow it up to supplement populations of that particular species out in the wild or to learn more about what we would need to do if we had to do those processes.

What would happen if these seeds weren’t being collected in a meaningful and directed way?

I think to put it simply and bluntly, I suppose, is that there would be species that would be going extinct. And we would be sitting there watching them go extinct because there wasn’t just the opportunity to have collected and securely stored away seed or propagation material of that particular species to grow up and reintroduce back into the wild. So, they have been in a number of places throughout Australia, there have been examples of species that as a result of these fires that we saw in earlier, you know, a few years ago, species effectively wiped out in the wild. We then have the opportunity to go back into the bank, withdraw the seed of those species, grow them up carefully in our nurseries, really skilled horticulturalists who are able to grow all sorts of things, grow them up, and then that material can then get carefully transported out to the site or a site that’s similar in some way so that we can restore that population or in some cases supplement the population. So, it really is quite profound it can be done that way.

You mentioned before that collecting seeds, storing them and making sure that they were exchanged between gardens wasn’t exactly a new thing. But then from around 2000 onwards the point of storing seeds began to change. And I’m wondering, I mean, it’s taking you back over two decades now, but do you remember the shifting conversations that were happening around that time and when that focus started to shift?

Yeah, and it really was through the 1990s, I suppose there was a general recognition that – and I think there was a lot of internal conversations within botanic gardens all around the world about what is the role of a botanic garden. Is it just to have a stamp collection of plant species that they displayed in the Botanic Gardens, which you know, has a really important role as being inspiring and of course being a beautiful place to go and have a picnic and wander around and perhaps get inspired by the whole diversity of life on the planet. But it needed to be more than that.

In order to be able to have a role in the facing biodiversity crisis, in the climate crisis, it needed to be actually out there doing proactive work for plant conservation. And the benefit that we have is the Botanic Gardens generally, as a group have a long term view on their program. So, it’s not a three year or five year funding cycle. We plant a tree, we have a strong expectation that it’s going to be there in 200 years and we do everything to make sure that that happens. So, it’s because of that long term role and that long term vision stability we were able to start thinking about we need to be proactively involved in plant conservation. We need to be out there collecting materials so that we do have it in our collections, in our seed banks and in the Botanic Gardens collections. And we have the technical expertise in terms of our gardeners and horticulturists to grow the most difficult species that you could expect to find and to look at new ways to grow things so that we can actually have a very strong role in that space.

Say you’ve got a plant or a type of plant that might be under threat and then that’s okay because you’ve got the seed bank. But to say the plant’s been under threat because of the impacts and the threats of climate change, the things that you’ve been talking about, say, rising sea levels, salinity, fire, flood, all of those things. So, if the plant’s already under threat, what are the considerations that you and the team working on the seed bank need to think about when making sure that what you’ve got in the seed bank can now thrive? Because once it’s out there in the natural environment, surely it’s exposed to the same threats that made it under threat in the first place.

Yeah, that’s a really interesting question and it’s something that we put a lot of thought and a lot of effort into and a lot of science into. I think the Wollemi pine is probably – it’s our poster child, if you like, of plant conservation. And it’s a great example of the sorts of considerations you need to take into place. The natural population is in this deep, deep gorge. But since 2004, maybe 10 years after it was discovered, we know that there’s been an invasive pathogen phytophthora that’s been introduced into the site. So, we’re keen to ensure its long-term survival.

So, we need to then start thinking about, do we create another site? Do we create another population? What other considerations do we need to take into place? You need to look at the environment, soil type, is this pathogen in the potential places that you want to look at? What is the climate likely to be now? What is the climate likely to be in 2050, 2070. Taking all of these considerations into account so that if you do establish a population of – a translocated, what we call a translocated population or re-wilding, if you like – If we do establish those populations that we think about how it’s likely to survive, because there’s a lot of effort gone into that in order to do. And you know, we’ve got really cool tools now with genomics and genetics to be able to say these are the number of individuals that need to use these and the best ones to use.

Tell us about the Restore & Renew program. What is that?

So, this is a program where we’re looking at ways in which we can – I don’t think it’s enough just to go out there and save species. We’ve got to do something positive about enhancing and restoring natural ecosystems that have been either cleared or damaged or the like. So, Restore & Renew is a program where we [are] looking at a whole range of species that are used quite frequently and regularly for restoration programs. So, by restoration programs, I mean programs where you’re planting in effectively probably agricultural fields or grasslands or whatever, you’re replanting an ecosystem.

So, what we’re wanting to do is to look at different species, collect across their whole geographic range, then do a genomic scan of how much variability there is across those species and relate their genomic relationships to the temperature of the particular locations that they’re collected from now. And so, if somebody is interested then in restoring a particular location, they can start to ask questions about, I really want to put these plant species back into this ecosystem that I’m restoring, but I want it to be able to be – have the best chance of being resilient in the face of climate issues in 2050 or 2070. So, to put it simply and probably a bit superficially in some ways, is that if I’m growing this eucalypt here, that might mean I collect from the farthest northern component of its range, because those individuals will be used to experiencing temperatures that are much hotter than where I’m planting. So, it’s about trying to use genetics and the tools and the technology that we have now to give the restored ecosystem the biggest and best chance to be resilient in 2050 or 2070, whatever the climate models that you’d like to use.

Is this where the term or the concept of genetic variability comes into play?

Yes. So, every organism has a level of genetic variability. In some it’s quite huge and lot of eucalypts, there’s really huge variation across its geographic range. A species like the Wollemi pine, it’s almost – it’s been in this gorge breeding with itself for probably tens of thousands of years and they’re almost all clones. So, there’s very little opportunity there. But what you want to do is to make sure that you’ve got representatives of that genetic variability in your restored population. So, whatever potential threat it might be faced, it has the best chance for those individuals that have the appropriate set of genes to be naturally resilient to that threat.

Is there a spectrum of poor to best practice when it comes to projects that focus on restoration, regeneration, reforestation? Because when you think of, for instance, programs that claim to offset flights, for instance, a lot of them about putting plants into the ground and it sounds like that fundamentally is what needs to be done, because I wonder whether there’s an element of greenwashing that happens with some programs as opposed to best practice of what you’re striving for here.

Yeah, there is absolutely the potential and what you might think are plantations that are being done for the best purposes, but because either they are just using a single clone of a species of a plant or, you know, in some cases they’re planting invasive species in that location. We see lots of examples of this in using Australian acacias and eucalypts in in parts of Africa. Or even not taking notice of the right attributes in terms of species diversity, genetic diversity, appropriate for the location, appropriate for the future climate issues, and then even just practical issues about making sure that the planting is done in a way that the plants are being produced so that their maximum health or they’re free of pathogens, they’re grown in a way that’s going to facilitate them actually establishing in the environment.

It’s not enough just to stick the plants in the ground and walk away. You have to actually follow up, you know, intervene maybe sometimes, use supplementary water, weed control. All of these things have to be done properly in order for it to be actually a restored area to get to the point where it does actually have the potential to be fixing carbon dioxide in a meaningful way.

I’m really interested in another area of work that the Botanic Gardens does, which is actually digital archiving as well, and digital collection. The herbarium at the Australian Botanic Garden in Mount Annan stores dried plant specimens and the gardens have just completed this massive undertaking of digitising those specimens. So, first of all, what does that actually mean to digitise them? And why is it important?

So, our herbarium collection is roughly 1.4 million specimens. The oldest specimens are those that have been – that were collected by Banks and Solander on Cook’s voyage. So, there are 830 odd specimens that were collected then. So, in 1770, so they were the first sort of European science that happened in the east coast of Australia at least. And they’re specimens that have been collected right up until – our guys are out this week collecting and adding to the collection.

We had the opportunity, when we moved the herbarium from the Sydney Garden site to the Mount Annan Garden site to engage with a company called Picturae, a Dutch company that had this fabulous conveyor system that you put the specimen on one end, it goes through it takes a photograph of the whole specimen at extraordinarily high resolution. So, you know, for somebody who’s looking at that image of that specimen, they can zoom down to it as though they’re looking down at the specimen through a binocular microscope. So, we went through that whole process as we moved it out to Mount Annan. So, those images are now available for anybody to look at, to use. But what it does do is it opens up the collections to researchers all around the world to be able to explore and to use it.

These specimens are really critical because they provide opportunities to look at the changes over time in the collection, you can look at a species that was collected in 1770, a species that was collected in 2022 and you can start to extrapolate changes. This may well be an opportunity to look at the impact of changing climates and the like. But you can also then start to look at evolutionary relationships, adaptability and all of those sorts of attributes. So, it’s really by unlocking that data. And if you’re interested in what might have been growing on your site in the 1950s, but it’s been cleared for so long, nobody’s got a record of it, herbaria have got these records and they can start to pull out all of the specimens pre 1950 in this region and give you a suite of species that you could then use to guide your restoration. So, there’s so many ways.

I think one of the cool things about the digitisation project is how it’s being used by all sorts of different people in different ways to do so, whether it’s artists looking to interpret the collection. Cultural historians who are looking to look at how people explored the environment over the 250 years since 1770 in different ways. So, there’s all sorts of different opportunities that should be doing that in that space. It’s fantastic.

You wrote an article for The Guardian earlier this year and the headline was so interesting and so is the story. The headline was Slave traders’ names are still stamped on native plants. It’s time to ‘decolonise’ Australia’s public gardens. Now we’ve heard the phrase and talked about the concept of decolonization I think in the Australian spheres for a while now in terms of landmarks, but I’m really interested in the dimension of the colonial history of Australia stamped out in plants themselves. In what ways are they stamped on the plants and why is it important to have this conversation?

Yeah, I think it’s really important for organisations like Botanic Gardens or, you know, Powerhouse we’re here, Australian Museum, those sorts of organisations that are collecting organisations to explore their history and why they were founded. Botanic gardens were founded on the premise – particularly British colonial botanic gardens, were founded on the premise of what are the plants in this country? What can we use them for? How can they foster the economic wealth of the empire, if you like. And so, we really do need to start to think about how we were founded, what we’re doing and why we’re doing it. And we need to reflect the First Nations history of these places properly. A

nd when you go through this whole premise of what we do as an organisation, particularly from the botanical taxonomy, is we always talk about finding a new species, describing a new species, which of course, you know, First Nations people have been here for tens of thousands of years. They probably used that plant species, probably knew what it was, had a name for it. This premise that it’s been sitting there undiscovered and unknown is inherently false.

Brett you’ve had such an incredible history with the Botanic Gardens and of course, you’ve talked about the ways in which you’ve seen the gardens evolve in your time working with them and even their roles and responsibilities change and shift. 34-year history coming up. Can I cast your mind into the future and the next 34 years ahead for the Botanic Gardens? How do you see the Botanic Gardens in 34 years? I think the year will be 2056 by that stage. I’ll definitely be quite ripe by that age. Where do you see the Botanic Gardens? Where do you see its role in climate change? How do you see its impact hopefully playing out by then?

I do hope that we will continue to have a meaningful impact on mitigation and adaptation to climate change. And I do think there’s a real role for being a place for community to engage with nature, to understand about nature, understand the precariousness of nature in this space, and to look at ways in which they can make meaningful differences. So, I do hope that that’s going to be an opportunity that the gardens will continue to embrace and explore.

Well, Brett, thanks so much for doing that work, not only at the gardens but here today with us all I really appreciate it.

Thank you, Ben.

Could you please join me in thanking our wonderful guest today, Brett Summerell, everyone. If you want to follow the program online or listen or watch conversations with climate leaders, including OzHarvest founder Ronni Kahn, former Australian of the Year Tim Flannery, businessman and activist shareholder Mike Cannon-Brookes, Dark Emu author Bruce Pascoe, you can always head to the website. Subscribe wherever you get your podcasts and visit the website where you’ll find details of course, how to join us here live at the Powerhouse. That’s 100climateconversations.com. Thank you so much.

This is a significant new project for the museum and the records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects that tell the stories of our time. It is particularly important to First Nations peoples to preserve conversations like this, building on the oral histories and traditions of passing down our knowledges, sciences and innovations which we know allowed our Countries to thrive for tens of thousands of years.